The present invention relates generally to fluid valve assemblies. Fluid valves are commonly used in a variety of applications, including public, residential, and commercial fixtures. Metering valves, for example, have been used where the need exists to control and meter a flow of fluid. Typically, the valve is spring biased to a closed state. An operator must manually actuate the valve, causing it to dispense a metered quantity of fluid before automatically shutting off due to the spring bias.
Self-returning valves are known that drive a valve to an open state through opposing cam surfaces. For instance, one such fixture includes a driver stem rotated by a handle at the stem's upper end. A flange extends radially outward from a bottom end of the drive stem immediately below a ring that is rotationally and axially fixed within the fixture housing. The flange defines a sloped cam surface that rides against a correspondingly sloped cam surface on the ring. As the stem rotates, the ring's cam surface drives the drive stem down against a plunger of a metering valve, thereby opening the valve and permitting water flow. A spring seated between the fixture housing and the driver stem flange pushes the drive stem upward when the operator releases the handle. The flange's cam surface rides back up the ring's cam surface so that the stem and handle rotate to their original position as the stem rises. The now-released metering valve then closes according to its metering operation.
The prior art valve includes a rotational stop within the fixture housing that blocks rotation of the drive stem flange beyond the point at which the stem flange pushes the metering valve to its fully open position.
Two examples of metering valves are disclosed in U.S. Pat. Nos. 5,655,748 and 5,451,030. These patents are commonly assigned to the present assignee, and their entire disclosures are incorporated by reference herein.